题目内容：

根据短文内容及所给提示，补全文中单词或用所给单词的正确形式填空

Last week, we had an interesting class. It was in the 1.(chemist) class，and our teacher asked us 2.(do) an experiment. The students were happy a3.this. We watched the experiment with full attention. Our teacher explained a4.the experiment went on. At last, the result appeared. We were 5.(puzzle) by the fact. Many things were really unexpected.